| Step | Hyp | Ref | Expression | 
						
							| 1 |  | slemuld.1 | ⊢ ( 𝜑  →  𝐴  ∈   No  ) | 
						
							| 2 |  | slemuld.2 | ⊢ ( 𝜑  →  𝐵  ∈   No  ) | 
						
							| 3 |  | slemuld.3 | ⊢ ( 𝜑  →  𝐶  ∈   No  ) | 
						
							| 4 |  | slemuld.4 | ⊢ ( 𝜑  →  𝐷  ∈   No  ) | 
						
							| 5 |  | slemuld.5 | ⊢ ( 𝜑  →  𝐴  ≤s  𝐵 ) | 
						
							| 6 |  | slemuld.6 | ⊢ ( 𝜑  →  𝐶  ≤s  𝐷 ) | 
						
							| 7 | 1 4 | mulscld | ⊢ ( 𝜑  →  ( 𝐴  ·s  𝐷 )  ∈   No  ) | 
						
							| 8 | 1 3 | mulscld | ⊢ ( 𝜑  →  ( 𝐴  ·s  𝐶 )  ∈   No  ) | 
						
							| 9 | 7 8 | subscld | ⊢ ( 𝜑  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ∈   No  ) | 
						
							| 10 | 9 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ∈   No  ) | 
						
							| 11 | 2 4 | mulscld | ⊢ ( 𝜑  →  ( 𝐵  ·s  𝐷 )  ∈   No  ) | 
						
							| 12 | 2 3 | mulscld | ⊢ ( 𝜑  →  ( 𝐵  ·s  𝐶 )  ∈   No  ) | 
						
							| 13 | 11 12 | subscld | ⊢ ( 𝜑  →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ∈   No  ) | 
						
							| 14 | 13 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ∈   No  ) | 
						
							| 15 | 1 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐴  ∈   No  ) | 
						
							| 16 | 2 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐵  ∈   No  ) | 
						
							| 17 | 3 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐶  ∈   No  ) | 
						
							| 18 | 4 | adantr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐷  ∈   No  ) | 
						
							| 19 |  | simprl | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐴  <s  𝐵 ) | 
						
							| 20 |  | simprr | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  𝐶  <s  𝐷 ) | 
						
							| 21 | 15 16 17 18 19 20 | sltmuld | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  <s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 22 | 10 14 21 | sltled | ⊢ ( ( 𝜑  ∧  ( 𝐴  <s  𝐵  ∧  𝐶  <s  𝐷 ) )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 23 | 22 | anassrs | ⊢ ( ( ( 𝜑  ∧  𝐴  <s  𝐵 )  ∧  𝐶  <s  𝐷 )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 24 |  | 0sno | ⊢  0s   ∈   No | 
						
							| 25 |  | slerflex | ⊢ (  0s   ∈   No   →   0s   ≤s   0s  ) | 
						
							| 26 | 24 25 | mp1i | ⊢ ( 𝜑  →   0s   ≤s   0s  ) | 
						
							| 27 |  | subsid | ⊢ ( ( 𝐴  ·s  𝐷 )  ∈   No   →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐷 ) )  =   0s  ) | 
						
							| 28 | 7 27 | syl | ⊢ ( 𝜑  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐷 ) )  =   0s  ) | 
						
							| 29 |  | subsid | ⊢ ( ( 𝐵  ·s  𝐷 )  ∈   No   →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐷 ) )  =   0s  ) | 
						
							| 30 | 11 29 | syl | ⊢ ( 𝜑  →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐷 ) )  =   0s  ) | 
						
							| 31 | 26 28 30 | 3brtr4d | ⊢ ( 𝜑  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐷 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐷 ) ) ) | 
						
							| 32 |  | oveq2 | ⊢ ( 𝐶  =  𝐷  →  ( 𝐴  ·s  𝐶 )  =  ( 𝐴  ·s  𝐷 ) ) | 
						
							| 33 | 32 | oveq2d | ⊢ ( 𝐶  =  𝐷  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  =  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐷 ) ) ) | 
						
							| 34 |  | oveq2 | ⊢ ( 𝐶  =  𝐷  →  ( 𝐵  ·s  𝐶 )  =  ( 𝐵  ·s  𝐷 ) ) | 
						
							| 35 | 34 | oveq2d | ⊢ ( 𝐶  =  𝐷  →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  =  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐷 ) ) ) | 
						
							| 36 | 33 35 | breq12d | ⊢ ( 𝐶  =  𝐷  →  ( ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ↔  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐷 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐷 ) ) ) ) | 
						
							| 37 | 31 36 | syl5ibrcom | ⊢ ( 𝜑  →  ( 𝐶  =  𝐷  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) ) | 
						
							| 38 | 37 | imp | ⊢ ( ( 𝜑  ∧  𝐶  =  𝐷 )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 39 | 38 | adantlr | ⊢ ( ( ( 𝜑  ∧  𝐴  <s  𝐵 )  ∧  𝐶  =  𝐷 )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 40 |  | sleloe | ⊢ ( ( 𝐶  ∈   No   ∧  𝐷  ∈   No  )  →  ( 𝐶  ≤s  𝐷  ↔  ( 𝐶  <s  𝐷  ∨  𝐶  =  𝐷 ) ) ) | 
						
							| 41 | 3 4 40 | syl2anc | ⊢ ( 𝜑  →  ( 𝐶  ≤s  𝐷  ↔  ( 𝐶  <s  𝐷  ∨  𝐶  =  𝐷 ) ) ) | 
						
							| 42 | 6 41 | mpbid | ⊢ ( 𝜑  →  ( 𝐶  <s  𝐷  ∨  𝐶  =  𝐷 ) ) | 
						
							| 43 | 42 | adantr | ⊢ ( ( 𝜑  ∧  𝐴  <s  𝐵 )  →  ( 𝐶  <s  𝐷  ∨  𝐶  =  𝐷 ) ) | 
						
							| 44 | 23 39 43 | mpjaodan | ⊢ ( ( 𝜑  ∧  𝐴  <s  𝐵 )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 45 |  | slerflex | ⊢ ( ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ∈   No   →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 46 | 13 45 | syl | ⊢ ( 𝜑  →  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 47 |  | oveq1 | ⊢ ( 𝐴  =  𝐵  →  ( 𝐴  ·s  𝐷 )  =  ( 𝐵  ·s  𝐷 ) ) | 
						
							| 48 |  | oveq1 | ⊢ ( 𝐴  =  𝐵  →  ( 𝐴  ·s  𝐶 )  =  ( 𝐵  ·s  𝐶 ) ) | 
						
							| 49 | 47 48 | oveq12d | ⊢ ( 𝐴  =  𝐵  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  =  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 50 | 49 | breq1d | ⊢ ( 𝐴  =  𝐵  →  ( ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ↔  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) ) | 
						
							| 51 | 46 50 | syl5ibrcom | ⊢ ( 𝜑  →  ( 𝐴  =  𝐵  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) ) | 
						
							| 52 | 51 | imp | ⊢ ( ( 𝜑  ∧  𝐴  =  𝐵 )  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) | 
						
							| 53 |  | sleloe | ⊢ ( ( 𝐴  ∈   No   ∧  𝐵  ∈   No  )  →  ( 𝐴  ≤s  𝐵  ↔  ( 𝐴  <s  𝐵  ∨  𝐴  =  𝐵 ) ) ) | 
						
							| 54 | 1 2 53 | syl2anc | ⊢ ( 𝜑  →  ( 𝐴  ≤s  𝐵  ↔  ( 𝐴  <s  𝐵  ∨  𝐴  =  𝐵 ) ) ) | 
						
							| 55 | 5 54 | mpbid | ⊢ ( 𝜑  →  ( 𝐴  <s  𝐵  ∨  𝐴  =  𝐵 ) ) | 
						
							| 56 | 44 52 55 | mpjaodan | ⊢ ( 𝜑  →  ( ( 𝐴  ·s  𝐷 )  -s  ( 𝐴  ·s  𝐶 ) )  ≤s  ( ( 𝐵  ·s  𝐷 )  -s  ( 𝐵  ·s  𝐶 ) ) ) |